H2O2 production at gas-diffusion cathodes made from agarose-derived carbons with different textural properties for acebutolol degradation in chloride media
2022
Zhang, Yanyu | Daniel, Giorgia | Lanzalaco, Sonia | Isse, Abdirisak Ahmed | Facchin, Alessandro | Wang, Aimin | Brillas, Enric | Durante, Christian | Sirés, Ignasi
The excessive cost, unsustainability or complex production of new highly selective electrocatalysts for H₂O₂ production, especially noble-metal-based ones, is prohibitive in the water treatment sector. To solve this conundrum, biomass-derived carbons with adequate textural properties were synthesized via agarose double-step pyrolysis followed by steam activation. A longer steam treatment enhanced the graphitization and porosity, even surpassing commercial carbon black. Steam treatment for 20 min yielded the greatest surface area (1248 m² g⁻¹), enhanced the mesopore/micropore volume distribution and increased the activity (E₁/₂ = 0.609 V) and yield of H₂O₂ (40%) as determined by RRDE. The upgraded textural properties had very positive impact on the ability of the corresponding gas-diffusion electrodes (GDEs) to accumulate H₂O₂, reaching Faradaic current efficiencies of ~95% at 30 min. Acidic solutions of β-blocker acebutolol were treated by photoelectro-Fenton (PEF) process in synthetic media with and without chloride. In urban wastewater, total drug disappearance was reached at 60 min with almost 50% mineralization after 360 min at only 10 mA cm⁻². Up to 14 degradation products were identified in the Cl⁻-containing medium.
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